The conventional passenger-side automotive inflatable restraint system comprises a reaction canister which is a trough-like member housing a folded airbag. An inflator chamber is associated with, and may be an integral part of, the canister. Conventionally, it takes the form of a hollow cylinder which encloses a gas generator and filter combination. Ports in the inflator chamber permit gas to enter and inflate the airbag.
The inflator chamber may be in the form of a tube having two open ends. Alternatively, it may be formed with one end open, the other end being closed by a base. In either case, it is customary to load the inflator chamber on site with the necessary elements. These elements include a tubular cylindrical filter pack formed of metallic wire mesh and non-metallic fibers. The filter pack absorbs heat from the combustion gases and inhibits solid particles from exiting the inflator.
The various elements for producing the inflating gas are loaded into the inflator pack to form a filter assembly. These include the gas generant which may be, for example, in the form of cylindrical or disc-shaped grains and an igniter which may take any of several forms. A preload spring is also contained within the filter assembly to maintain the generant under compression. Suitable end caps and bases, as required, are used to complete the assembly. One major problem with this prior art approach is that the generant must be transported in bulk to the assembly lines. This can result in breakage and dusting of the generant, thereby reducing it to its most dangerous condition while present in an assembly line location where it poses danger both to persons and material.
Accordingly, it is a primary object of the present invention to provide a unitary, generant-loaded, filter assembly which may be completely assembled at the generant manufacture site and delivered to the assembly line as a drop-in component. Furthermore, this component may be inspected and certified before assembly into the inflator chamber, thereby reducing the cost associated with rejection. Other objects, features, and advantages will become apparent from the following description and appended claims.